Enrichment of tocols from rice germ oil using supercritical carbon dioxide

Abstract

An efficient process was developed for enrichment of tocols from rice germ oil (RGO) using supercritical carbon dioxide (SC-CO2). Tocols were efficiently enriched in residue by removal of fatty acid methyl ester from the esterified RGO using SC-CO2. The enrichment of tocols was carried out at an operating pressure of 12.415.8 MPa, an operating temperature of 4060 degrees C and a carbon dioxide flow rate of 5.0 L min-1. The combination of 13.8 MPa pressure and 60 degrees C temperature was selected as the most suitable for efficient enrichment of tocols. The level of tocols (1270 mg/100 g) in the residue obtained at these operating conditions was six times higher than the tocols level (192 mg/100 g) of the starting material, namely esterified RGO. There were no significant differences in relative percentages of tocols homologues between esterified RGO and the residue obtained by SC-CO2 extraction.